Chap. 14*] Hand) Fingers, &c, ijg 



per part of the laft bone of the four fingers. Its ufe 

 is to bend the laft joint of the fingers. 



The lurnbricales arife from the four tendons of the 

 preceding mufcle> and are inferted into the outer fides 

 'of the broad tendons of the interoflei mufcles. They 

 increafe the flexion of the fingers. 



The extenfor digitorum communis arifes from the 

 outer tondyle of the os humeri, and is inferted into the 

 polterior part of all the fingers by a tendinous expan* 

 fion. It extends all the fingers. 



The mufcles, which roll the radius on the ulna> are, 



The fupinator radii longus, which arifes from the 

 external ridge of the os humeri above the external 

 cond.yle. It is inferted into the outer fide of the infe- 

 rior extremity of the radius. Its effect is to roll the 

 radius outwards, and confequently to turn the palm of 

 the hand upwards. 



The fupinator radii brevis, which arifes from the 

 external condyle of the os humeri and pofterior fur- 

 face and outer edge of the ulna. It is inferted into 

 the head, neck, and tubercle of the radius. It rolls 

 the radius outwards, and turns the pairn of the hand 

 upwards. 



The pronator radii teres, which originates from the 

 -internal condyle of the os humeri and coronoid pro- 

 cefs of the ulna. It is inferted into the pofterior part 

 of the radius, about the rhiddle of that b-*ne. Its effecl: 

 is to roll the radius, with the hand, inwards, and coq- 

 fequendy to turn the back of the/ hand upwards, or to 

 lay the hand prone. 



The pronator radii quadratus arifes from the inner 

 and lower part of the ulna. Its fibres, running tranf- 

 verfely, are inferted into the anterior part of the radius 

 oppofice to their origin. 



For the motion of the thumb are placed in the 

 fore -arm, 



N 2 The 



